Judicious pairing of redundant radials from nested radar systems to optimize radar surface current mapping at Cape Hatteras

The PEACH (Processes driving Exchange At Cape Hatteras) project included 1.5 years of field sampling designed to examine forcing and shelf response resulting in shelf edge exchange. A crucial component of this project was the combination of a low-frequency CODAR radar array with a higher frequency WERA radar array. As always, two or more radars estimating radial velocities (vector magnitudes pointing towards or away from each site on a 2-D spherical coordinate system) over a particular area of ocean are necessary to form a vector velocity field at gridpoints where the radials from the two systems cross at sufficiently non-parallel angles. A consequence of the high density of radars operating during PEACH was overlapping coverage of 3-4 sets of radials over substantial portions of the study site. This afforded us the opportunity to perform trials, combining different subsets of radial combinations within “HFR_prog” open source software. Efforts were designed to minimize errors from using too many radial inputs from less ideal radial crossing angles. One important goal is to optimize high resolution coverage over Diamond Shoals, where a gap exists between nominally paired high resolution WERA sites. Circulation over areas like Diamond Shoals, which are not amenable to current meter moorings, are difficult to address with other measurement techniques. This data manipulation may help expand understanding of exchange dynamics at Cape Hatteras.